With its VTC 250 L EMAG introduces its first Lean- type vertical shaft turning machine. The machine has been developed especially to serve as a stand-alone, or to be used in chaku-chaku production lines.
EMAG: Shaft by shaft …
26/08/2009 - Oliver Hagenlocher
The VTC for small batch production?
Yes! The VTC 250 L is designed as a stand-alone for the machining of small component batches. The machine builder from Salach may be better known in the world of medium and large batch production, but with the VTC 250 L he intends to transfer the advantages provided by his mass production machines to the manufacture of smaller batches. Markus Woitsch defines the new business segments as follows: “In the mass production of components process integrity plays the decisive role; and we can fall back on a lot of experience in this particular field. We now want to take advantage of this experience and apply it to small batch production. The vertical construction offers us the unimpeded chip flow we want. It almost completely eliminates the need for the manual removal of chips. This is particularly important in soft machining, as the process frequently generates high chip volumes.” However, the vertical construction is not the only thing where the machine scores. The men from Salach have also had a brilliant idea in the matter of automation. “Our VTC 250 L is in competition with the classical horizontal turning machine. However, it works in our favour that we have in the VTC 250 L a fully-fledged turning machine that also includes automation. Retooling the VTC 250 L is just as easy/difficult as retooling a horizontal machine; but ours is the advantage of not having to load every workpiece manually. On the VTC 250 L this is done by the turret”, explains Herr Woitsch.
The EMAG Chaku-Chaku principle
The chaku-chaku principle is a Japanese invention, whereby “chaku-chaku” stands for “loading, loading”. It is a variant of flow line production, where all process steps in the manufacture of a workpiece are carried out in close proximity to each other. The space-saving vertical construction of the VTC 250 L allows for a number of machines to be combined to form compact manufacturing cells, making them suitable for mass production. The VTC 250 L’s footprint is about 60% less than that of a comparable horizontal turning machine. The chaku-chaku principle also tries to achieve the desired separation of operator and machine by automating the processes that tie the former to the latter. This includes workpiece loading and unloading, which – on the VTC 250 L – is done by the gripper in the turret. This gripper collects the raw-part from the loading station and takes it to the clamping position. Once the machining process has been completed the workpiece is removed from the machine the same way. Thus, all VTC 250 L stations work independently, without requiring any input from the operator. To all intents and purposes, all the operator has to do is to take the workpieces from the first to the second machine. As every VTC 250 L is equipped with a workpiece buffer, changes in the production process can be acted on with great flexibility. The system also allows for zero-defect production, as the workpiece – as soon as it comes off the machine - is subjected to a visual inspection and then checked more thoroughly at a separate measuring station.
The VTC 250 L design
Die VTC 250 L is characterised by its sturdy and rigid construction. At its core is the machine base in Mineralit® (polymer concrete). The damping properties of this material are eight times those of cast iron, making it especially suitable for hard machining (hard turning). It also leads to an extended tool life and a better surface finish. Spindle motor, main spindle, turret and electrical cabinet are all fluid-cooled. With its high power rating (29/38 kW), its high speeds and its extremely sturdy EMAG turret for 40 mm tool shanks the VTC 250 L is a highly efficient turning center for shaft machining. Headstock and steadies are CN-controlled, with the tailstock being stationary. For complete-machining purposes the 12-position disc-type turret can be equipped with a workpiece gripper and up to eleven stationary turning or live drilling and milling tools.
The advantages of the VTC 250 L:
- The machine can be used for stand-alone applications or in a chaku-chaku type manufacturing cell.
- Integrated workhandling. The EMAG turret reduces the outlay for automation and peripherals. Raw-part and finished component storage areas form an integral part of the machine.
- Headstock and steadies are CN-controlled. Set-up and retooling times are reduced.
- The vertical construction of the machine ensures the unhindered flow of chips, preventing the formation of clusters.
- Small footprint through compact, vertical machine design.
- Great accessibility and the machine’s operator friendliness provide for short set-up and retooling times.
- Direct driven machine axes and modern control systems reduce the need for sensors.